Manostat



March 3l, 1959 J. F. TAPLIN 2,879,783

MANOSTAT A Filed NQv. 7, 1956 United States Patent O MANOSTAT John F.Taplin, West Newton, Mass.

Application November 7, 1956, Serial No. 620,920

16 Claims. (Cl. IS7-116.3)

This invention is concerned with a new and novel construction of amanostat used in controlling the feed pressure to air gauges. Manostatsare designed for use in controlling and maintaining at a substantiallyconstant ligure the downstream pressure of a fluid which is supplied bya higher upstream pressure.

Thepresent manostat may be termed an indirect operated low-driftregulating valve and one of the objects of the invention is theprovision of means for causing prompt and adequate opening of the supplyvalve immedately upon the downstream pressure falling below the requiredvalue to bring the pressure up to the required value. Conversely, whenthe downstream pressure is restored to the predetermined value, thesupply is promptly cut olf. If, at any time, there should be excessdownstream pressure a relief valve will function to drain olf suchexcess pressure thereby to maintain the pressure at the predeterminedvalue within very narrow limits.

In maintaining the predetermined value the mechanism so functions thateven when gaseous fluid on the downstream side is not being used ordrawn E there will be a continuous opening and closing of the severalvalves so that a small quantity of the uid is being constantly bled olfto theatmosphere, all resulting in the downstream pressure liuctuatingcontinuously between very narrow limits. Under other conditions when thedownstream fluid is being used in quantity, the supply valve will becorrespondingly opened fully either to maintain the downstream pressureor if it cannot be maintained because of excessive use, to re-build itin a minimum time.

A further object of the invention is the provision of a construction inwhich the supply valve and the relief valve may readily be removed forcleaning purposes and if need be, the entire unit may be completelydisassembled for inspection or replacement of any parts, if necessary.

A further object of the invention is the inclusion of means in themanostat whereby the controlled downstream pressure may be selected, asdesired, within a wide range, varying from slightly above atmospheric toa small amount below the available upstream pressure.

These and other objects of the invention will be more clearly understoodas the description proceeds with the aid of the accompanying singleligure of the drawing which shows the manostat in vertical section.Since the manostat in a preferred form is substantially symmetrical inall vertical sections, it is believed that a single sectional view willbe suliicient for illustrative purposes.

Referring now more specifically to the drawing, there is a casinggenerally indicated at 2 having an upper section 4, an intermediatesection 6 and a lower section 8. The sections 6 and 8 are separated by aspacer section 10 which is utilized in mounting an internally locatedannular element referred to as a spacer ring 12.

Lower section 8 has a suitable inlet or upstream port 14 which may beconnected by a pipe 16 with a source of high 'pressure uid. An outlet ordownstream port 18 2,879,783 Patented Mar. 31, 1959 may be connected bypipe 20to a suitable container in which the uid is stored at therequired regulated pressure.

Between the inlet and outletports 14 and 18 is a passage 22 having avalve seat 24 adapted to be engaged by a supply valve 26, which valve isconstantly urged `.towards closed position by spring 28, supported inturn by a screw threaded removable plug 29.

A valve stem 30 extends upwardly from valve 26 and has on its upper endrelief valve 32 which is adapted to make engagement with valve seat 36appropriately mounted on spacer ring 12. Leading from the relief valve32 through spacer ring 12 and spacer section 10 to the atmosphere isk aradially extending port 36 through which downstream lluid may escape ifthe presure exceeds the predetermined value. Relief valve 32 is smallerin diameter than passage 22, so that upon removal of plug 29, supplykValve 26 and relief valve 32 may be removed for repair or replacement.

Within the contines of the generally cylindrical upper section 4 and theupper part of the intermediate section 6 is a control chamber 38 whichis in communication with the outlet port 18 and downstream pressure bymeans of one or more passages 40 extending through the spacer section10. A horizontal wall 42 integral with the intermediate section 6constitutes the y'lower wall of control chamber 38. On the lower side ofwall 42 is a pilot pressure chamber 44 which chamber is closed on itslower side by the previously referred to spacer ring 12 and aninterposed diaphragm 46. This ring is held in place by the said upperdiaphragm 46 and a lower diaphragm 48. Upper diaphragm 46 has adownwardly turned circular movable convolution 50 and the lowerdiaphragm 48 has an upwardly turned circular movable convolution 52. Theouter peripheries of diaphragms 46 and 48 are clamped between thesections 6, 10 and 8 in the manner shown, being rmlysecured by aplurality of bolts 54 of which two are shown and which are threaded attheir lower ends to make threaded engagement with lower section 8,thereby to draw all of the several sections tightly together. The spacerring 12 and the upper and lower diaphragms 46 and 48 together constitutea movable wall 55 subject on its under side to the outlet pressure andon its upper side to the pressure in pilot pressure chamber 44. Thepressure in chamber 44 is a variable pressure ranging from atmosphericas a minimum to the substantially outlet pressure as a maximum, all ofwhich will be explained in detail hereinafter.

Centrally located of wall 42 is a port 56 leading from control chamber38 to pilot pressure chamber 44. This port may be closed by upwardmovement of a pilot valve 58 having an upwardly extending stern 60 whichis aixed to a suitable support 62 mounted on the underside of ameasuring capsule or pressure sensitive device 64. This device of thinsheet metal is circular in horizontal section and on its upper side isaliixed to a threaded tubular adjusting stern 66 which stem makesthreaded engagement with an internally threaded boss 68 that extendsupwardly from the center of the upper wall 70 of upper section 4. Thepassage 72, which is in direct connection with the interior of deviceY64, leads to the atmosphere through the laterally extending opening 74.

A handle 76 is aixed to the upper end of stern 66 so that by rotationthereof the position of pilot valve 58 with respect to valve seat 56 maybe varied as needed. Byy

Centrally located in pilot pressure chamber 44 is a small helicalcompression spring 78, stronger than spring 28,`

which bears on threaded pad 80 and acts constantly to urge the spacerring 12do'wnwardly. The exterior ange of pad A8() -serves `to-hold thecenter interior Aperiphery of diaphragm 46 tightly in place on the uppersurface of spacer ring 12. The flange on the lower threaded pad 82, inwhich is also locatedvalve seat 34, serves a similar purpose to hold thecentral portion of diaphragm 48 securely against the lower side of thespacer ring 12.

A small restricted passageway S4 leads from pilot pressure chamber 44 tothe atmosphere.` This is a veryl small opening in the order of .010" indiameter and its purpose will shortlybe explained.

Diaphragms 46 and 48 are aperturedat those areas in alignment with port40 so that uid may How freely between outlet chamber 18 and controlchamber 38. Thus the downstreampressure is at all' times present in thecontrol'` chamber 38.

Withthe foregoing construction in mind, the operationy of the manostatwillA Vnow be explained.` lf we'start the operation with the pressureonA the downstream side below the desired value and with the pressure inthe control chamber 38 at the same reduced pressure, pilot valve 58 willbe open and due to the low pressure in outlet port 18 the movable wall Scomprised of spacer ring 12 and diaphragms 46 and 48 will be forceddownwardly by spring 78 sufficiently to have engaged relief valve 32,and acting through stem 30, to have moved supply valve 26 downwardly tomaximum open position. Under these conditions relief valve 32 beingengaged by valve seat 34 will be closed.

With supply valve 26 open, the high pressure upstream supply of iluidwill flow through port 22 and thence through the outletl port 18 to thedownstream container. Gradually the downstream pressure will build up toappreach the desired value. As this pressure increases downstream, thepressure in control chamber 38 will correspondingly increase andlikewise uid owing through open port 56 will cause a build-up ofpressure in pilot pressure chamber 44. Since at this` stage uid willenter chamber 44 through port 56 faster than it can escape through smallrestricted passageway 84, the pressure in control chamber 38 and pilotpressure chamber 44 will be substantially the same so long as pilotvalve 58 remains open.

As the downstream pressure is increased and the desired value isapproached (and this pressure is determined by the setting of valvestern 66 and its related pilot valve 58), the pressure in controlchamber 38 will increase correspondingly to cause gradual collapse ofdevice 64 to raise valve 58 to closed position. As soon as valve 58closes, the pressure in pilot pressure chamber 44 drops rapidly as theliuid exhaustsv to the atmosphere through passageway 84.A Thus a largepressure diierential acting upwardly on diaphragm 48 with respect todownward pressure on diaphragm 46 develops causingv the movable wall 55to move upwardly at an accelerated rate permitting corresponding upwardmovement of relief valve 32` and supply valve 26 under the influence ofthe spring 28. Upon suiiicient upward movement of movable wall 55valvef26 will be closed and the desired downstream pressure will havebeen attained.

The following explanation of ther functioning of the valve will show howthe downstream pressure is continuously thereafter maintained at thisvalue. Let us assume that some of the downstream iluid is used, therebyto cause a drop in the downstream pressure. Immediately the pressurefalls below the required value, the pressure in control chamber38correspondingly falls, causing slight but immediate opening' of pilotvalve 58. This small opening of valve 58 is nevertheless much largerthantherestricted passageway 84- and hence, due to the small 'volume ofpilot pressure chamber 44, thepressure in chamber 44 instantly builds upto a Apressure substantiallyin'excess of atmospheric andv may, ifpilot-valve 58 is Sopen/suiciently, reach a ligure substantially equalto control chamber 38. With the effective forces on the upper and lowersides of movable wall 5S, now substantially equal, spring 78 acts tomove movable wall 5S downwardly immediately, thereby opening supplyvalve 26 an appreciable amount, thus enabling high pressure upstream uidto iiow in large quantity into the outlet chamber, thereby to restorethe downstream pressure quickly to its required gure.

ln the form of movable wall shown the effective area of diaphragm 46 onwhich the pressure in chamber 44 acts may be somewhat largerwthan theeffective area of diaphragm 48 on which the downstream pressure acts,thus giving a quicker response than would be the case if the diaphragmswere equal ineffective area. However, it is to be understood that thediaphragms may be of equal or unequal areas depending on the particulartype of response desired.

From the foregoing explanation, it is believed clear that a slight..opening of pilot' valve 58 will produce an immediate-andsubstantialopening of supply' valve 26.

Thus, alsmall deviation of downstream pressure below the desired valuewill result in substantial opening of the supply valve 26 to provideimmediate restoration of the required pressure'.

Conversely, over-running on the high side is limited because, uponclosure of pilot valve 58 which occurs asl soon as the required pressureis restored in control chamber 38, there follows a substantial andimmediate `drop,

.in the pressure in pilot pressure chamber 44, thus causing quick upwardmovement of movable wall 55 accompanied by corresponding quick closureof supply valve 26.

If uid is not being withdrawn from the downstream supply, then anyleakage that. may occur, either through relief valve 32, pilot valve 58or other valves or connections associated with the downstream tank orcontainer,. will be compensated for in the same manner just describedbut all of the valve movements will be of a limited nature justsuflicient to constantly restore the downstream pressure to the requiredvalue.

If it is desired to raise the controlled downstream pressure to a newhigher value, then valve stem 66 should be screwed downwardly toincrease the normal opening between pilot valve 58 and valve seat S6. Inthis way greater pressure will be required in control chamber 38 beforevalve S8 is closed and hence, supply valve 26 will stay open for alonger time so that this required higher pressure can be built up.Conversely, if the controlled downstream pressure is to be reduced, thenvalve stern- 66 will be screwed upwardly to decrease the normal open ingbetween valve 58 and valve seat 56.

Since atmospheric pressure in any given location` is substantiallyconstant, it is apparent that if desired the handle 76 can be calibratedto permit the manostat to be setto give any required pressure. lf thehandle is not calibrated, then reference may be made to a pressure gageon the downstream container and the handle adjusteduntil the desireddownstream pressure has been arrived at after which the desired pressurewill be maintained until changed by further adjustment of the handle.

It is my intention to cover all changes and modications of the exampleof the invention herein chosen for pur.

poses of the disclosures which do not constitute de partures'from'thespirit and scope of the invention.

I claim:

l. A manostat comprising a casing including an inletA port'and an outletport and a movable supply valve and atmospheric to substantially outletpressure, a second.

valve responsive to said outlet pressure, said pilot pres-` sure beingdetermined by the degree of opening of said secondl valvev and means foropening and closing saidv supply'valve in accord with movement of saidwall.

2. A manostat as set forth in claim 1, said wall being carried in saidcasing by two spaced diaphragms.

3. A manostat as set forth in claim 1, said movable wall havingdifferent effective areas on opposite sides.

4. A manostat as set forth in claim 2, said wall having a relief portextending therethrough connecting the outlet port with the atmosphereand a relief valve for` closing said relief port movable in unison withsaid supply valve.

5. A manostat as set forth in claim 1, said means for opening andclosing said supply valve comprising an element extending from saidsupply valve to said wall.

6. A manostat as set forth in claim 5, said wall being carried in saidcasing by two spaced diaphragms, a relief port extending from saidoutlet port between said diaphragms to the atmosphere, said elementincluding a relief valve on the end thereof for closing said relief portwhen said wall moves toward said supply valve.

7. A manostat as set forth in claim 6, and spring means for urging saidsupply and relief valves in the direction of said wall and other springmeans for urging said wall toward said relief valve to augment the forceexerted on said one side.

8. A manostat as set forth in claim 1, spring means for urging said wallin the direction of said supply valve to assist in opening said supplyvalve and other spring means urging said supply valve toward closedposition.

9. A manostat as set forth in claim 1, said means for opening saidsupply valve including a spring constantly urging said wall toward saidsupply valve and said means for closing said supply valve comprising asecond spring effective to move said supply valve toward closed positionas said wall is moved away from said supply valve seat.

10. A manostat comprising a casing having therein an inlet port, anoutlet port, a first passage therebetween, a supply valve forcontrolling the ow of uid through said iirst passage from said inletport to said outlet port, a control chamber, a second passage from saidoutlet port to said control chamber, a pilot pressure chamber having awall xed with respect to said casing, a pilot valve port through saidwall leading from said control chamber to said pilot pressure chamber, amovable element mounted on said casing by spaced flexible diaphragms,one diaphragm forming a wall of said pilot pressure chamber and theother diaphragm forming a wall of said outlet port, a relief passage insaid element extending from said outlet port to the atmosphere, a reliefvalve fixed with respect to said supply valve for closing said reliefpassage, spring means constantly urging said supply valve and reliefvalve toward closed position, other stronger spring means constantlyurging said element toward said relief valve, a restricted passage fromsaid pilot pressure chamber to the atmosphere, a pressure measuringdevice in said control chamber movable as the pressure in said controlchamber fluctuates, a pilot valve actuated by said pressure measuringdevice for closing said pilot valve port when said control chamberpressure increases above a predetermined degree and for opening saidpilot valve port when said control chamber pressure decreases below saidpredetermined degree, whereby pressure in said outlet port below saidpredetermined degree will cause said pressure measuring device to opensaid pilot valve and said element will be moved downwardly to close saidrelief valve and to open said supply valve and whereby pressure in saidoutlet port above said predetermined degree will cause said device toclose said pilot valve thereby to reduce the pressure in said pilotpressure chamber and said element will be moved upwardly to permitclosing of said supply valve.

11. A manostat comprising a casing having an inlet port and an outletport, a movable supply valve and a j fixed supply valve seatintermediate the said ports, means urging said supply valve towardclosed position, a movable relief valve xed with respect to said supplyvalve and a movable cooperating relief valve seat, a control chambersubject to outlet port pressure, a pilot pressure chamber with a movablewall subject to opposing variable forces and supporting said reliefvalve seat, a restricted orifice leading from said pilot pressurechamber to the atmosphere, a pilot valve port leading from said controlchamber to said pilot pressure chamber with a fixed valve seat therein,a pressure sensitive device in said control chamber subject to thepressure in said outlet port, a pilot valve cooperating with said fixedvalve seat for opening and closing said port under the influence ofchanging control chamber pressure acting on said pressure sensitivedevice, whereby the pressure in said pilot pressure chamber can bequickly varied from atmospheric to substantially outlet port pressureand said movable wall will be shifted according to the opposing forcesto which it is subjected, said supply valve being opened by downwardmovement of said movable wall when said relief valve seat is inengagement-with said relief valve, and said supply valve being closedwhen said relief valve seat is out of engagement with said relief valve.

l2. A manostat for maintaining the downstream pressure at a requiredvalue, comprising a casing having an inlet port and an outlet port and asupply valve therebe tween, a movable wall for actuating said supplyvalve, said wall subject to the pressure in said outlet port on one sideand means for varying the pressure on the other side from a minimum notless than atmospheric to a maximum not more than said outlet pressure,said pressure varying means comprising a pilot pressure chamber having afixed exhaust port and being in communication with said outlet port, thepressure in said pilot pressure chamber being controlled by a movablepilot valve actuated by the outlet pressure, the parts so constructedand arranged that when the outlet pressure is below the required value,said pilot valve and supply valve will be open and when said `outletrpressure is above said required value, said pilot valve and supplyvalve will be closed.

13. A manostat comprising a casing including an inlet port and an outletport and a supply valve therebetween, a movable wall supported by spaceddiaphragms for opening said supply valve, spring means urging saidsupply valve toward closed position, a control chamber connected withsaid outlet port, a pilot pressure chamber having a restricted outlet tothe atmosphere, a pilot port opening from said control chamber into saidpilot pressure chamber, a pilot valve for said pilot port controlled bythe pressure in said control chamber, said movable wall subject to thepressure in said outlet port and said pilot pressure chamber, otherspring means urging said movable wall toward said supply valve forassisting the pressure in said pilot pressure chamber in moving saidwall toward said supply valve to open said valve.

14. A manostat as set forth in claim 13, a relief passage to theatmosphere through said wall and casing, and a relief valve for closingsaid passage and moving in unison with said supply valve.

15. A manostat comprising a casing including an inlet port and an outletport and a supply valve therebetween,

a movable wall supported by spaced diaphragms, means for transmittingmovement of said wall to said supply valve, spring means urging saidsupply valve toward closed position, a control chamber connected withsaid outlet port, a pilot pressure chamber having a restricted outlet tothe atmosphere, a pilot port opening from said control chamber into saidpilot pressure chamber, a pilot valve for said pilot port controlled bythe pressure in said control chamber, said movable wall subject to thepressure in said outlet port and said pilot pressure chamber, otherspring means urging said movable wall toward said supply valve, theeffective operating areas of the opposed sides of said movable wallbeing unequal.

16. A manostat comprising a casing including an inlet port and an outletport and a movable supply valve and fixed seat therebetween, a movablewall, a pilot pressure chamber, one side of said wall being subjected tothe out let pressure and the other Side fsaid Wall being Sub- PressureAf 1=`1f11at1ie .Said Pilot Valve whereby the presjectedto the pressure,in said pilot pressure chamber, said sure in said plqt pressure chambermay be varied when pilot pressure chamber having an yintake port and anexsaid gutlet pressure varies,

haust port, the intake port providing for the transmission of outletpressure to said pilot pressure chamber` and the 5 vRefel'eg-1es Citedin the tile of this patent exhaust port providing for transmission ofpressure in said UNITED STNIES PATENTS pilot pressure chamber to theatmosphere, a pilot valve for controlling flow of fluid through lone ofthe ports of v21,48'565() Grove et al. Nov. 8, 1949 said pilot pressurechamber and means subject to the outlet 2,761,464 Faust 1....-, Sept. 4,1956

